[eng] The core of this PhD dissertation is basically twofold : On one hand, I get some new results on the relationship between compact groups and bounded hyperimaginaries, extending a little bit the classical results of Lascar and Pillay in Hyperimaginaries And Automorphism Groups. On the other hand, I prove some new results around the so called "stable forking" property, more specifically that a simple theory T has stable forking if Teq has. Quite surprisingly, the proof is not so straigtforward.[spa] En este texto se trata, por una parte, de la relación entre grupos compactos e hiper-imaginarios acotados, y por otra parte se prueba que una teoría T tiene la propiedad de bifurcación estable si i solo si Teq la tiene.